Self-induced splitting of spiral-shaped spreading depression waves in chicken retina

Abstract

Spreading depression (SD) of electroencephalographic activity is a dynamic wave phenomenon in the central nervous system (CNS). The retina, especially the isolated chicken retina, is an excellent constituent of the CNS in which to observe the dynamic behavior of the SD wave fronts, because it changes its optical properties during a SD attack. The waves become visible as milky fronts on a black background. It is still controversial what the basic mechanistic steps of SD are, but certainly SD belongs to the self-organization phenomena occurring in neuronal tissue. In this work, spiral-shaped wave fronts are analyzed using digital video imaging techniques. We report how the inner end of the wave front, the spiral tip, breaks away repeatedly. This separation process is associated with a Z-shaped trajectory (extension approximately 1.2 mm) that is described by the tip over one spiral revolution (period 2.45+/-0.1 min). The Z-shaped trajectory does not remain fixed, but performs a complex motion across the retina with each period. This is the first time, to our knowledge, that established imaging methods have been applied to the study of the two-dimensional features of SD wave propagation and to obtaining quantitative data of their dynamics. Since these methods do not interfere with the tissue, it is possible to observe the intrinsic properties of the phenomenon without any external influence.

Spiral Waves in Nonlocal Equations

“…where s is Euclidian distance in Fourier space, then multiplying both sides of (8) by the denominator of F [w] and taking the inverse two-dimensional Fourier transform result in (4). The coupling function w is given by the inverse Fourier transform of (9), which is (7), and is plotted in Figure 1.…”

“…In a neural context, spiral waves have been observed in the turtle visual cortex [34] and the chicken retina [8] and hippocampal slices [14] and are widely thought to occur in the disinhibited human visual cortex, where they are perceived as hallucinatory images [9,10,39]. There is also speculation that spiral waves may be involved in epileptic seizures [41].…”

Extracellular matrix and its role in conveying glial/neural interactions in health and disease

“…In axons and the heart these waves are physiological whereas in retina and cortex they are not, and are therefore associated with pathophysiological events. The same dynamics that produces waves produces other types of macroscopic electrochemical patterns: standing patterns and self-sustained sequences of spirals (Dahlem and Müller [8]; Fernandes de Lima and Hanke [11,14,15]). These patterns can be associated with "petit mal" seizures, complex seizures perceptual distortions and transient global amnesia that either impair consciousness or distort perception.…”

Bi-Stable Spiral Waves: Stepped Spiral Waves

“…Spiral waves are typical patterns in RD systems [6]- [11] which have been observed throughout such diverse systems as chemical reactions [12] [13] [14] [15], fluid convection [16] [17], microorganism populations [18], Xenopus laevis oocytes [19], cardiac muscle [20] [21], chicken retinae [22], and model RD systems [23] [24] [25] [26] [27]. They have been extensively studied both experimentally and theoretically.…”